My first cook was with one Costco boneless butt. I honestly don't remember the weight, the original packaging was long gone and we don't have a food scale, plus I didn't think to weigh it anyway. I trimmed off the fat cap and threw it on the smoker for about 7 or 8 hours. My temps were pretty steady around 220-250 for most of the cook. I used a full water pan and did not foil. Turned out great.
Funny story, my only other experience with smoking a butt was on a OTG and it took 10 hours (and wasn't tender enough when I pulled it, but guests were getting hungry). So this time I planned for a 10-12 hour cook. I just happened to go out around the 7 hour mark to take an internal temp and to my surprise found it was basically done. I hadn't even gotten my bbq tongs cleaned up from putting the raw meat on, so I left it on the smoker while I got my utensils cleaned. Went back out and did a probe/fork test in a couple of spots to verify it was tender enough, pulled it off, rested it, pulled it, and ate it for a few days. Good stuff.
And now I want to do another shoulder.
